1871, Now there is father; he is au fait in all these matters; has a theory for every case of whooping-cough, — and a mission school. — Elizabeth Stuart Phelps in The Silent Partner, collected in Popular American Literature of the 19th CenturyISBN 0195141407, p. 857

1999, In that case, it would help to have a benevolent deity who is au fait with those complexities — but that there is such a deity is a feature of Stoic theology. — R.J. Hankinson in The Cambridge History of Hellenistic Philosophy, ISBN 0521250285, p. 535

2003, This may sound needless to the professional who is au fait with the history and direction of the investigation. — D R J Laming in Understanding Human Motivation: What Makes People Tick?ISBN 0631219838, p.4